Chorioamnionitis

Updated on February 12, 2017

Chorioamnionitis is a bacterial infection that causes irritation and inflammation of the amnion and chorion fetal membranes. Typically, this bacterial infection occurs in late-state pregnancies as a result of the bacteria traveling from the vagina to the uterus especially after the fetal membranes have ruptured and during labor, though may times the exact cause of the infection is unknown. While this is not necessarily a life-threatening condition, it is important to evaluate the situation if you begin to have abnormalities appear within the last month of pregnancy. Please evaluate the following information to see if you may have chorioamnionitis or are at risk of developing it.

CausesWhile there are multiple ways to become infected with chorioamnionitis, the most common method of infection is via prolonged ruopture of the fetal membranes and or long labor that leaves the vagina and the uterus exposed to one another. This allows bacteria from the vagina (or in some cases, the anus) to travel into the uterus which will lead to infection. The infection is relatively common and occurs in many pregnancies within the United States, especially when diagnosed by pathologic examination of the placenta. Complications can include infections of the baby, in the pelvic region, uterine infections and blood clots in the pelvis and lungs.

DiagnosisThere are two essential ways to make the diagnosis of chorioamnionitis: Clinical, from special physical signs and symptoms, and pathological, from examining the placenta. The infection is typically discovered through the presence of uterine tenderness and or abnormal vaginal discharge that is caused by a premature rupture of membranes, along with a fever, though it also can happend without rupture of the fetal membranes. Other symptoms such as rapid fetal heartbeat, sweating and an unusual-smelling discharge from the vagina can also be used to physically evaluate whether or not a mother has chorioamnionitis.

Confirmation of the bacteria can be obtained through a blood sample from the mother as well as sampling the amniotic fluid to inspect for bacteria. An ultrasound can also be used to examine the health of the fetus.

TreatmentThe treatment of chorioamnionitis is relatively straightforward and simple. Ultimately, a mother needs to give birth as this is the final “treatment” of the bacterial infection. A doctor may prescribe the mother antibiotics, consisting of amoxicillin, gentamicin and metronidazole, to help combat the infection while the mother carries the baby to full-term. In combination with delivery of the baby and an antibiotic treatment, the bacteria will be destroyed shortly after delivery. Once the baby is delivered, it should also be checked for the bacterial infection and if present, can also receive treatment in the form of antibiotics.

PrognosisWith proper treatment and evaluation of both the mother and baby, chorioamnionitis poses little threat to full-term babies. Preterm babies diagnosed with the bacteria have a 10-20% chance of developing pneumonia, a 1-2% chance of developing meningitis and up to a 15% chance of death due to respiratory and brain complications. Full-term babies' risks of these complications are far lower and in the vast majority of cases, respond well to typical antibiotic treatment. It is important to deliver the baby as soon as possible after the development of chorioamnionitis but it is also a balancing act as babies that are exposed to the bacteria and are delivered pre-term will be more likely to suffer the aforementioned complications.